<!doctype html>

<title>06 Property Types - React From Zero</title>

<script src="https://unpkg.com/react@15.4.2/dist/react.js"></script>
<script src="https://unpkg.com/react-dom@15.4.2/dist/react-dom.js"></script>
<script src="https://unpkg.com/babel-core@5.8.38/browser.min.js"></script>

<div id="app"></div>

<script type="text/babel">

// Components get created to encapsule stuff
// that should be together in one place and for reuse
// Reuse requires the user of the component to supply the correct properties
// So we can define a type of each property and set defaults

function MyComponent(props) {
  return (
    <div className={props.className}>
      <h1>Hello</h1>
      <h2>{props.customData}</h2>
    </div>
  )
}

// Add the propTypes (function-)property to the component function
// to let in validate its (element-)properties
MyComponent.propTypes = {
  // React supplies us with a bunch of types, like string
  customData: React.PropTypes.string,
}

// Add defaultProps (function-)property to set the defaults
// if nothing was provided by the user
MyComponent.defaultProps = {
  customData: 'default',
  className: 'default-class',
}

// This will show a warning in the console, because customData should be a string
var reactElement = <MyComponent customData={123}/>

// This will use the defaults
reactElement = <MyComponent/>

var renderTarget = document.getElementById('app')

ReactDOM.render(reactElement, renderTarget)

</script>